Axial flow compressor



G. D. FRASER AXIAL FLOW COMPRESSOR Aug, 20, 1963 2 Sheets-Sheet 1 Filed Feb. 27, 1961 R o T N E V m HIS GROVE R D. FRASER XTO Aug. 20, 1963 s. D. FRASER AXIAL FLOW COMPRESSOR 2 Sheets-Sheet 2 Filed Feb. 27, 1961 R 5\ m kw mm R E m M m R WY 6 MB H 6 United States Patent 3,101,171 AXllAL FLOW CG-MPREhSOR Grover D. Fraser, Painted Post, NDEL, assignor to lugersoll-Rand Qompany, New York, I l-Y a corporation of New Jersey Filed Feb. 27, 1961, Ser. No. 91,942 5 (Ilaims. (Cl. 230-443) This invention relates to axial flow rotary gas compressor s and particularly to compressors having intermeshing spiral lobe rotors adapted to positively displace fluid within a casing.

The heat of compression developed in such a compressor increases the temperature progressively from the inlet to the outlet end at which are located bearings which cannot be safely operated at high temperatures. The usual anti-friction bearings used for such compressors must be kept below a temperature of around 180 F. while the heat of compression in their vicinity will commonly reach 350 F. or more. In the past this has necessitated the use of oil cooling systems for the bearings or for the compression chamber which in some instances is cumbersome, especially when such compressors are to be portable.

The primary object of this invention is to eliminate the above noted objectional oil cooling system for the rotor bearings located at the outlet end of a rotary gas compressor.

Other important objects of this invention include: to provide a simple and eflicient means tor cooling and isolating the bearing of a rotary g-as compressor from the heat of the compressed gas being discharged from the compressor; to provide a simple way of cooling the portion of a gas compressor casing which is subject to the heat of the compressed gas; to provide a means for mounting a bearing of an axial flow gas compressor at the compressed gas out-let end of the compressor where it is isolated and protected from the beat of the com pressed gas; and to provide a simple, comp-act andrelatively inexpensive design of an axial flow gas compressor. I

The objects of this invention are attained briefly by arranging the rotor hearing at the outlet end of the rotor, adj accnt the compressed gas outlet in the compressor casing, so that the bearing is substantially isolated from the heat of the compressed gas and locating the gas intake conduit :sothat the bearing is cooled by the intake gas flowing to-the inlet of the gas compressor. Arranging the intake gas to pass over the bearing at the outlet end of the compressor rotor also results in cooling the portion of the compressor casing adjacent the outlet end of the rotor.

Other objects and advantages of the invention will be in part obvious and in part pointed out in the following description taken in conjunction with the accompanying drawing in which 7 FIGURE 1 is a top view partly in longitudinal section of an axial flow compressor constructed in accordance with the practice of the invention,

FIG. 2 is a cross section on a reduced scale taken at the line 22 of FIG. 1 looking in the direction of the arrows, and

FIG. 3 is a side view of the compressor of FIG. 1 in section at the line 3-3 of FIG. 1 looking in the dhection ot the arrows.

Referring to the drawing the axial flow compressor is provided with a casing it within which are adapted to rotate a pair of interrncshing rotors 0-1": the spiral lobe type, rotor 12 being the female rotor and 14 the male rotor. Casing is provided with an inlet opening 15 and a discharge outlet 16 which are conventional. At v the inlet end of casing 16' is provided a housing 18 having a flange 2th for connection to a suitable driving motor (not shown), and at the discharge end is provided an end wall 22 which may be formed integrally with casing 1i and with a discharge nozzle as adapted to be connected with a suitable discharge conduit (not shown), for conveying the compressed fluid from. the compressor discharged at outlet 16.

Rotor 12 is provided with a shaft end 28 passing through end wall 22 and is rotatably supported by antitriction bearing 3%) housed in a support 32. Likewise, a shaft end 34 of rotor 14 extends through wall .22 to the anti-friction bearing 36 mounted in a support 38, in this instance formed integrally with support 32. Supports 32 and 33 are spaced as far as is reasonably practical from end wall 22 to leave a space between them, the supports being mounted on wall 22 by means of webs 40 which may be, as shown herein, tor-med integrally with end Wall 22 and supports 32 and 38.

A suitable cover 42 encloses the outer ends ot supports 32 and 3S. Supports 32 and 3-8 and bearings 3&9 and 36, respectively, housed therein, :are kept cool by the passage of about them and over the connecting Webs 4021s it passes to inlet 15. This is accomplished by providing a wall 44 cooperating with casing ll) to form 'a passageway to for air to flow axially from the outlet end of the compressor to inlet 15. Wall 44 in this instance is formed integrally with casing 1d and passageway as starts at an opening 43 in end wall 22, adjacent the flange 24 and terminates near the end flange 5d of casing 18 to which housing 18 is bolted.

The above construction for-ms an annular inlet or gas intake chamber 51 surrounding the shafts 28 and 34 and the bearings 30 and 36. This annular chamber 51 is bordered on one side by the outer face of the casing end wall 22 and on the other side by the bearing supports 32 and 38 and the cover 42. The gas intake chamber 51 contains the bearing supporting webs 4t) and opens radially "outward for gas to enter the chamber and cool the bearings 30 and 36 and the end wall 22 before entering the passageway 46 on the way to the gas inlet 15. The above gas intake chamber 51 combines with the passageway as to form the intake gas conduit for the compressor.

In order to direct inlet air about supports 32 and 38 and the webs 49/, a filter 52 is mounted on end wall 22 and the flange 24 to encircle supports 32 and 38 and consists of a hat strip continuous and conforming to the contour of rib 54 on end wall 22 and resting thereon, its outer edge being mounted in a supporting bracket of sheet material 56 which contains that outer edge and has a flat face 53 cut to conform to the flange 6d of cover 4 2 and secured thereto by suitable crews 62. j

A protective guard and air guide for filter 52 is provided at 64- bent to conform to the contour of flange 24 and headed at its outer edge 66 to form an inlet space 68 in the vicinity of cover 42 and open at the bottom, as shown in FIGS; 2 and 3. It will be seen that air introduced into the compressor at inlet 15 is drawn into the space 68 and at the bottom opening of guard 64th1ou-gh filter 52 which not only cleanses the incoming air but has the efiect of distributing the introduced air evenly about the surface of the filter 52. The air thus passes over the Webs 40 cooling them and the supports 32 and 38, and to some end extent end wall 22. The inlet air will then passthrough opening 48 and passageway 46 to inlet 15 into the interior of casing 10.

As the air progresses toward outlet 16, the heat of compression raises the temperature of the air and heats up the rotors 12 and 14 and shafts 28 and 34, which will be the main source. of heat transferred to bearings 30 and 36. Shafts 28 and 34 are however to some extent cooled by the passage of the inlet air over them in the space or chamber 51 between supports 32 and 38 and end Wall 22,.

In the construction shown in the drawings air is prevented from leaking from the interior of casing into the inlet or intake chamber 51 by means of labyrinth seals provided on sleeves '70 on shafts 2S and 34 between bearings 30 and 36 and rotors 12 and 14.

Thus, by the above construction, are accomplished the objects hereinbefore referred to.

I claim:

1. A rotary gas compressor in which gas is compressed in an axial direction parallel to the rotary axis of the compressor and discharged in a heated condition from the compressor, said compressor comprising: a gas compressing rotor, said rotor adapted to receive gas, compress the gas axially as it rotates and discharge the gas in a heated condition caused by its compression; a casing surrounding said'rotor; an outlet in said casing adjacent one end of the rotor for discharging compressed and heated gas from the rotor; an inlet in said casing for admitting intake gas to said rotor; said casing including an end Wall located adjacent said outlet Where it is heated by the compressed gas being discharged through said outlet; said rotor having a shaft at said one end extending through said end wall in gas sealing relationship; lubricated bearing means rotatably supporting said shaft and being spaced from the outer face of said end Wall; and intake gas conduit means having one end connected to said inlet for conducting intake gas to said inlet and being partly formed by said outside face of said casing end Wall to cause the intake gas to pass in heat exchange relationship with said end wall whereby said end wall is cooled by said intake gas and said end wall is separated and insulated from said bearing means by a current of intake gas to prevent said bearing means from being overheated.

2. A rotary gas compressor in which gas is compressed in an axial direction parallel to the rotary axis of the compressor and discharged in a heated condition from the compressor, said compressor comprising: a casing; a gas compressing rotor rotatively mounted in said casing, said rotor adapted to receive gas, compress the gas axially as it rotates and discharge the gas in a heated condition caused by its compression; an outlet in said casing adjacent one end of said rotor for discharging compressed and heated gas from said rotor; an inlet in said casing for admitting intake gas to said rotor; said casing including an end well located adjacent said outlet where it is subjected to the heated compressed gas being discharged through said outlet; a rotor shaft fixed on said one end of said rotor and projecting through said end wall of said casing in a gas sealing relationship; lubricated hearing means rotatively supporting the projecting portion of said rotor shaft and being spaced axially outward from the outer face of said casing end wall; spaced web means fixed on said outside face of said casing end wall for supporting said bearing means thereon, said web means being arranged to leave the space between said outside face and said bearing means relatively free for a current of gas to fiow therebetween; cover means fixed on said casing end Wall to provide an "annular gas intake chamber surrounding said bearing means and disposed between said bearing means and said outside face of said casing end wall; said cover means including an intake gas opening extending circumferentially around said annular gas intake chamber; and a conduit interconnecting said annular gas intake chamber with said inlet in said casing to conduct intake gas from said chamber to said inlet.

3. The gas compressor of claim 2 including; an annular filter surrounding said annular gas intake chamber and extending across said intake gas opening to filter the intake gas entering said annular gas intake chamber.

4. The gas compressor of claim 2 wherein: said conduit interconnecting said annular gas intake chamber with said inlet is formed by a passage contained in said casing so that the portion of the casing surrounding said passage is cooled by the flow of intake gas through said passage.

5. The gas compressor of claim 2 including: a second rotor intermeshing with the first rotor to cause gas to be compressed as it flows axially through said casing toward the one end of the first rotor Where said outlet is located; and said inlet is located in an axial direction upstream from said outlet.

References Cited in the file of this patent UNITED STATES PATENTS 709,968 Day Sept. 30, 1902 1,851,193 Laraque Mar. 29, 1932 2,346,398 Rohr, et a1. Apr. 11, 1944 2,361,855 McCormack Oct. 31, 1944 2,407,987 Landberg Sept. 24, 1946 2,504,230 Smith Apr. 18, 1950 2,612,845 Byram, et al. Oct. 7, 1952 2,776,086 Selden Jan. 1, 1957 2,804,260 Nilsson, et a1. Aug. 27, 1957 2,918,907 Hausmann. Dec. 29, 1959 FOREIGN PATENTS 116,207 Switzerland Nov. 1, 1926 238,840 Great Britain Aug. 27, 1925 523,308 Germany Apr. 22, 1931 1,249,171 France Nov. 14, 1960 

1. A ROTARY GAS COMPRESSOR IN WHICH GAS IS COMPRESSED IN AN AXIAL DIRECTION PARALLEL TO THE ROTARY AXIS OF THE COMPRESSOR AND DISCHARGED IN A HEATED CONDITION FROM THE COMPRESSOR, SAID COMPRESSOR COMPRISING: A GAS COMPRESSING ROTOR, SAID ROTOR ADAPTED TO RECEIVE GAS, COMPRESS THE GAS AXIALLY AS IT ROTATES AND DISCHARGE THE GAS IN A HEATED CONDITION CAUSED BY ITS COMPRESSION; A CASING SURROUNDING SAID ROTOR; AN OUTLET IN SAID CASING ADJACENT ONE END OF THE ROTOR FOR DISCHARGING COMPRESSED AND HEATED GAS FROM THE ROTOR; AN INLET IN SAID CASING FOR ADMITTING INTAKE GAS TO SAID ROTOR; SAID CASING INCLUDING AN END WALL LOCATED ADJACENT SAID OUTLET WHERE IT IS HEATED BY THE COMPRESSED GAS BEING DISCHARGED THROUGH SAID OUTLET; SAID ROTOR HAV- 